A sign on the sheet of assertion or on any other area, made by a single action or series of acts of scribing and expressive, according to the conventions of this system [of existential graphs], of an intelligible state of things, shall be called a graph-replica. The general type of all possible graph-replicas which would be similar to a given graph-replica in every significant respect, shall be called a graph.

A sign on the sheet of assertion or on any other area, made by a single action or series of acts of scribing and expressive, according to the conventions of this system [of existential graphs], of an intelligible state of things, shall be called a graph-replica.

A heavily marked uninterrupted line on the sheet of assertion, having two extremities and no branching shall be called a line of identity and shall be a graph asserting the identity of all the individuals denoted by its points (all which being heavily marked denote individuals).

The assertion of that which is unintelligible (i.e. absurd) not being a graph shall be called the pseudograph, and may be represented by filling the entire area in which it is, so as to leave room for nothing else.